MONITORING AND QUANTIFYING THE ENVIRONMENTAL CHANGE DETECTION OF LAKE KOLLERU AND THE SURROUNDING MANDALS USING REMOTE SENSING TECHNIQUES

Land Use and Land Cover (LULC) are significantly being altered globally. Lake Kolleru, one of the largest fresh water lakes in India, located in the state of Andhra Pradesh, is one example of a wetland ecosystem that requires constant monitoring. It is known for its ecological, biological and hydrological functions. In the past few years this lake had undergone many significant changes resulting in its deterioration due to anthropogenic activities in and around it. Attempts to impede its degradation have been made in the recent past due to which it is slowly recuperating. However, human encroachments in the lake have not completely stopped after various restoration projects. The present study focuses on monitoring and quantifying the changes that have occurred in and around Lake Kolleru to gain a historical perspective by temporal analysis as well as to understand the present status. Land Use Land Cover class categories were defined as Aquapond , Agriculture , Barrenland or non-crop or young crop , Water logged marshy area and Residential or built-up area . The overall image classification accuracies for the years 1988, 1993, 2000, 2004 and 2010 were 65.6%, 72%, 69.2%, 66.8%, and 73.2%, respectively. High classification accuracy was observed for certain individual categories of interest. Poor classification accuracy was observed in categories of Water logged marshy area and Residential or built-up area accounting for high commission error, because of similar spectral reflectance. The Land Use Land Cover dynamics show, that there were significant changes in the temporal periods 1988-1993, 1993-2000, 2000-2004 and 2004-2010. There was a drastic increase of 44% in Aquapond category from 1988 to 2004 followed by a decrease of 18.5% by 2010. Agriculture was observed as declining throughout all the temporal periods. Barren land category was observed as decreasing until 2004 with a slight increase by 2010. Decreases in Agriculture and Barrenland or non-crop or young crop were due to their conversion to Aquapond. Similar results were interpreted by the land transformation processes. Anthropogenic activities such as extensive agriculture and aquaculture are the major driving factors influencing changes in Land Use Land Cover and land degradation in the Lake Kolleru study area. The limitations of this study were unavailability of aerial photos and high resolution spectral images such as PAN images from the Indian Remote Sensors due to budget consideration. The other major limitation was the lack of ground- truth data with field observations